Fans of Elon Musk and commercial space exploration are buzzing over the news! Back in 2002, when Musk first established the private aerospace company SpaceX, he did so with the intent of creating the technologies needed to reduce the cost of space transportation and enable crewed missions to Mars. And for the past few years, industry and the general public alike have been waiting on him to say when missions to Mars might truly begin.
Earlier this morning, Elon Musk did just that, when he tweeted from his company account that SpaceX plans to send a Dragon capsule to Mars by 2018. Despite talking about his eventual plans to mount crewed missions to Mars in the coming decades, and to even build a colony there, this is the first time that a specific date has been attached to any plans.
What was also indicated in the announcement was that the missions would be built around the “Red Dragon” mission architecture. As a modified, unmanned version of the Dragon capsule, this craft was conceived back in 2013 and 2015 as part of the NASA Discovery Program – specifically for Mission 13, a series of concepts which are scheduled to launch sometime in 2022.
Though the idea was never submitted to NASA, SpaceX has kept them on hand as part of a proposed low-cost Mars lander mission that would deploy a sample-return rover to the Martian surface. The mission will be deployed using a Falcon Heavy rocket, based on the mission profile and the illustrations that accompanied the announcement.
This mission would not only demonstrate SpaceX’s ability to procure samples from the Martian environment and bring them back to Earth – something that only federal space agencies like NASA have been able to do so far – but also test techniques and equipment that human crews will be using to enter the Martian atmosphere.
And if all goes well, we can expect that Musk will push forward with his plans for both crewed missions, and the development of all the necessary architecture to being work on his Mars Colonial Transporter, which he hopes to use to begin ferrying people to Mars to build his planned colony.
Stay tuned for more in-depth analysis of this announcement from our resident expert, Ken Kremer!
Now that SpaceX has successfully and safely demonstrated the upright recovery of their Falcon 9 booster that flew to the edge of space and back on Dec. 21 – in a historic first – the intertwined questions of how did it fare and what lies ahead for the intact first stage stands front and center.
In Kubrick’s and Clark’s 2001 Space Odyssey, there was no question of “Boots or Bots”[ref]. The monolith had been left for humanity as a mileage and direction marker on Route 66 to the stars. So we went to Jupiter and Dave Bowman overcame a sentient machine, shut it down cold and went forth to discover the greatest story yet to be told.
Now Elon Musk, born three years after the great science fiction movie and one year before the last Apollo mission to the Moon has set his goals, is achieving milestones to lift humans beyond low-Earth orbit, beyond the bonds of Earth’s gravity and take us to the first stop in the final frontier – Mars – the destination of the SpaceX odyssey.
Ask him what’s next and nowhere on his bucket list does he have Disneyland or Disney World. You will find Falcon 9R, Falcon Heavy, Dragon Crew, Raptor Engine and Mars Colonization Transporter (MCT).
At the top of his working list is the continued clean launch record of the Falcon 9 and beside that must-have is the milestone of a soft landing of a Falcon 9 core. To reach this milestone, Elon Musk has an impressive array of successes and also failures – necessary, to-be-expected and effectively of equal value. His plans for tomorrow are keeping us on the edge of our seats.
CRS-5, the Cargo Resupply mission number 5, was an unadulterated success and to make it even better, Elon’s crew took another step towards the first soft landing of a Falcon core, even though it wasn’t entirely successful. Elon explained that they ran out of hydaulic fluid. Additionally, there is a slew of telemetry that his engineers are analyzing to optimize the control software. Could it have been just a shortage of fluid? Yes, it’s possible they could extrapolate the performance that was cut short and recognize the landing Musk and crew dreamed of.
The addition of the new grid fins to improve control both assured the observed level of success and also assured failure. Anytime one adds something unproven to a test vehicle, the risk of failure is raised. This was a fantastic failure that provided a treasure trove of new telemetry and the possibilities to optimize software. More hydraulic fluid is a must but improvements to SpaceX software is what will bring a repeatable string of Falcon core soft landings.
“Failure is not an option,” are the famous words spoken by Eugene Kranz as he’s depicted in the movie Apollo 13. Failure to Elon Musk and to all of us is an essential part of living. However, from Newton to Einstein to Hawking, the equations to describe and define how the Universe functions cannot show failure otherwise they are imperfect and must be replaced. Every moment of a human life is an intertwined array of success and failure. Referring only to the final frontier, in the worse cases, teams fall out of balance and ships fall out of the sky. Just one individual can make a difference between his or a team’s success. Failure, trial and error is a part of Elon’s and SpaceX’s success.
He doesn’t quote or refer to Steve Jobs but Elon Musk is his American successor. From Hyperloops, to the next generation of Tesla electric vehicles, Musk is wasting no time unloading ideas and making his dreams reality. Achieving his goals, making milestones depends also on bottom line – price and performance into profits. The Falcon rockets are under-cutting ULA EELVs (Atlas & Delta) by more than half in price per pound of payload and even more with future reuse. With Falcon Heavy he will also stake claim to the most powerful American-made rocket.
Musk’s success will depend on demand for his product. News in the last week of his investments in worldwide space-based internet service also shows his intent to promote products that will utilize his low-cost launch solutions. The next generation of space industry could falter without investors and from the likes of Musk, re-investing to build demand for launch and sustaining young companies through their start-up phases. Build it and they will come but take for granted, not recognize the fragility of the industry, is at your own peril.
So what is next in the SpaceX Odyssey? Elon’s sights remain firmly on the Falcon 9R (Reuse) and the Falcon Heavy. Nothing revolutionary on first appearance, the Falcon Heavy will look like a Delta IV Heavy on steroids. Price and performance will determine its success – there is no comparison. It is unclear what will become of the Delta IV Heavy once the Falcon Heavy is ready for service. There may be configurations of the Delta IV with an upper stage that SpaceX cannot match for a time but either way, the US government is likely to effectively provide welfare for the Delta and even Atlas vehicles until ULA (Lockheed Martin and Boeing’s developed corporation) can develop a competitive solution. The only advantage remaining for ULA is that Falcon Heavy hasn’t launched yet. Falcon Heavy, based on Falcon 9, does carry a likelihood of success based on Falcon 9’s 13 of 13 successful launches over the last 5 years. Delta IV Heavy has had 7 of 8 successful launches over a span of 11 years.
The convergence of space science and technology and science fiction in the form of Musk’s visions for SpaceX is linked to the NASA legacy beginning with NASA in 1958, accelerated by JFK in 1962 and landing upon the Moon in 1969. The legacy spans backward in time to Konstantin Tsiolkovsky, Robert Goddard, Werner Von Braun and countless engineers and forward through the Space Shuttle and Space Station era.
The legacy of Shuttle is that NASA remained Earth-bound for 30-plus years during a time that Elon Musk grew up in South Africa and Canada and finally brought his visions to the United States. With a more daring path by NASA, the story to tell today would have been Moon bases or Mars missions completed in the 1990s and commercial space development that might have outpaced or pale in comparison to today’s. Whether Musk would be present in commercial space under this alternate reality is very uncertain. But Shuttle retirement, under-funding its successor, the Ares I & V and Orion, cancelling the whole Constellation program, then creating Commercial Crew program, led to SpaceX winning a contract and accelerated development of Falcon 9 and the Dragon capsule.
SpaceX is not meant to just make widgets and profit. Mars is the objective and whether by SpaceX or otherwise, it is the first stop in humankind’s journey into the final frontier. Mars is why Musk developed SpaceX. To that end, the first focal point for SpaceX has been the development of the Merlin engine.
Now, SpaceX’s plans for Mars are focusing on a new engine – Raptor and not a Merlin 2 – which will operate on liquified methane and liquid oxygen. The advantage of methane is its cleaner combustion leaving less exhaust deposits within the reusable engines. Furthermore, the Raptor will spearhead development of an engine that will land on Mar and be refueled with Methane produced from Martian natural resources.
The Raptor remains a few years off and the design is changing. A test stand has been developed for testing Raptor engine components at NASA’s Stennis Space Center. In a January Reddit chat session[ref] with enthusiasts, Elon replied that rather than being a Saturn F-1 class engine, that is, thrust of about 1.5 million lbf (foot-lbs force), his engineers are dialing down the size to optimize performance and reliability. Musk stated that plans call for Raptor engines to produce 500,000 lbf (2.2 million newtons) of thrust. While smaller, this represents a future engine that is 3 times as powerful as the present Merlin engine (700k newtons/157 klbf). It is 1/3rd the power of an F-1. Musk and company will continue to cluster engines to make big rockets.
To achieve their ultimate goal – Mars colonization, SpaceX will require a big rocket. Elon Musk has repeatedly stated that a delivery of 100 colonists per trip is the present vision. The vision calls for the Mars Colonization Transporter (MCT). This spaceship has no publicly shared SpaceX concept illustrations as yet but more information is planned soon. A few enthusiasts on the web have shared their visions of MCT. What we can imagine is that MCT will become a interplanetary ferry.
The large vehicle is likely to be constructed in low-Earth orbit and remain in space, ferrying colonists between Earth orbit and Mars orbit. Raptor methane/LOX engines will drive it to Mars and back. Possibly, aerobraking will be employed at both ends to reduce costs. Raptor engines will be used to lift a score of passengers at a time and fill the living quarters of the waiting MCT vehicle. Once orbiting Mars, how does one deliver 100 colonists to the surface? With atmospheric pressure at its surface equivalent to Earth’s at 100,000 feet, Mars does not provide an Earth-like aerodynamics to land a large vehicle.
In 1952, Werner Von Braun in his book “Mars Projekt” envisioned an armada of ships, each depending on launch vehicles much larger than the Saturn V he designed a decade later. Like the invading Martians of War of the Worlds, the armada would rather converge on Mars and deploy dozens of winged landing vehicles that would use selected flat Martian plain to skid with passengers to a safe landing. For now, Elon and SpaceX illustrate the landing of Dragon capsules on Mars but it will clearly require a much larger lander. Perhaps, it will use future Raptors to land softly or possibly employ winged landers such as Von Braun’s after robotic Earth-movers on Mars have constructed ten or twenty mile long runways.
We wait and see what is next for Elon Musk’s SpaceX vision, his SpaceX Odyssey. For Elon Musk and his crew, there are no “wives” – Penelope and families awaiting their arrival on Mars. Their mission is more than a five year journey such as Star Trek. The trip to Mars will take the common 7 months of a Hohmann transfer orbit but the mission is really measured in decades. In the short-term, Falcon 9 is poised to launch again in early February and will again attempt a soft landing on a barge at sea. And later, hopefully, in 2015, the Falcon Heavy will make its maiden flight from Cape Canaveral’s rebuilt launch pad 39A where the Saturn V lifted Apollo 11 to the Moon and the first, last and many Space Shuttles were launched.
The Falcon Heavy is the brainchild of billionaire entrepreneur Elon Musk, SpaceX CEO and founder, and illustrates his moving forward with the firm’s next giant leap in spaceflight.
The rocket is designed to lift over 53 tons (117,00 pounds) to orbit and could one day launch astronauts to the Moon and Mars.
The commercial Falcon Heavy rocket has been under development by SpaceX for several years and the initial launch is now planned for later this year from Launch Complex 39A at the Kennedy Space Center (KSC) in Florida.
The new rocket is comprised of three Falcon 9 cores.
The Falcon Heavy will be the most powerful rocket developed since NASA’s Saturn V rocket that hurled NASA’s Apollo astronauts to the Moon in the 1960s and 1970s – including the first manned landing on the Lunar surface by Neil Armstrong and Buzz Aldrin in July 1969.
Here is the updated animation of the SpaceX Falcon Heavy flight and booster recovery:
Video Caption: Animation of SpaceX Falcon Heavy launch and booster recovery. Credit: SpaceX
The video shows the launch of the triple barreled Falcon Heavy from Launch Complex 39A at NASA’s Kennedy Space Center in Florida. Then it transitions to the recovery of all three boosters by a guided descent back to a soft touchdown on land in the Cape Canaveral/Kennedy Space Center area.
SpaceX, headquartered in Hawthorne, CA, signed a long term lease with NASA in April 2014 to operate seaside pad 39A as a commercial launch facility for launching the Falcon Heavy as well as the manned Dragon V2 atop SpaceX’s man-rated Falcon 9 booster.
Launch Complex 39A has sat dormant for over three years since the blastoff of the final shuttle mission STS-135 in July 2011 on a mission to the International Space Station (ISS).
SpaceX is now renovating and modifying the pad as well as the Fixed and Mobile Service Structures, RSS and FSS. They will maintain and operate Pad 39A at their own expense, with no US federal funding from NASA.
When it does launch, the liquid fueled Falcon Heavy will become the most powerful rocket in the world according to SpaceX, generating nearly four million pounds of liftoff thrust from 27 Merlin 1D engines. It will then significantly exceeding the power of the Delta IV Heavy manufactured by competitor United Launch Alliance (ULA), which most recently was used to successfully launch and recover NASA’s Orion crew capsule on its maiden unmanned flight in Dec. 2014
SpaceX recently completed a largely successful and history making first attempt to recover a Falcon 9 booster on an ocean-going “drone ship.” The rocket nearly made a pinpoint landing on the ship but was destroyed in the final moments when control was lost due to a loss of hydraulic fluid.
Read my story with a SpaceX video – here – that vividly illustrates what SpaceX is attempting to accomplish by recovering and ultimately reusing the boosters in order to dramatically cut the cost of access to space.
Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.
SpaceX CEO Elon Musk announces lawsuit protesting Air Force launch contracts while speaking at the National Press Club in Washington, DC on April 25, 2014
Elon Musk, CEO and founder of the upstart commercial launch venture SpaceX, announced at a press conference today, Friday, April 25, that SpaceX is filing suit against the Federal Government to protest and break the US Air Force’s awarding of lucrative launch contracts for high priority national security satellites to a sole rocket provider – United Launch Alliance (ULA) – on a non competitive basis.
The gloves are officially off in the intensely mounting duel over multibillion dollar Air Force military launch contracts between SpaceX and ULA.
“The official protest document will be available Monday, April 28th at www.freedomtolaunch.com and will be filed with the United States Court of Federal Claims in Washington, D.C.,” said SpaceX in an official statement.
Musk said the Air Force launch contract with ULA amounted to a continuing monopoly, was unfair by blocking SpaceX from competing for launches of surveillance satellites and would cost taxpayers billions of extra dollars in coming years.
“What we feel is that this is not right – that the national security launches should be put up for competition and they should not be awarded on a sole source, uncompeted basis,” said Musk at the briefing called on short notice and held at the National Press Club in Washington, DC.
The latest Air Force launch contract dated to December 2013 guarantees the “block buy” purchase of 36 rocket cores from ULA for national security launches for the DOD, NRO and other government agencies, at a significantly reduced cost compared to earlier contracts.
A further 14 cores were to be awarded on a competitive basis, including bids from SpaceX and others who seek to gain Air Force certification. Several of those launch awards have now been deferred indefinitely.
ULA is a joint venture between aerospace giants Boeing and Lockheed Martin, formed in 2006, that has launched over 80 satellites to orbit and beyond including many NASA science and mission probes like Orion EFT-1, Curiosity, MAVEN, TDRS and more.
It manufactures the Delta IV and Atlas V unmanned, expendable rocket families that are currently the only boosters certified to launch the high value military payloads at issue in the lawsuit announced on Friday by Musk.
The newest versions of the Delta and Atlas rockets – known as EELV’s (Evolved Expendable Launch Vehicles) have had nearly flawless records of success since being introduced some dozen years ago by the companies individually, before the ULA merger.
Musk wants his company’s newer and he says much cheaper Falcon 9 and Falcon Heavy rockets to be certified by the Air Force and included in the competition for launch contracts.
To date the Falcon 9 has launched only 9 times. Only four of those were in the new and more powerful configuration needed by the Air Force.
Musk is not asking that the launches be awarded outright to SpaceX. But he does want the Air Force contract cancelled and re-competed.
“We’re just protesting and saying that the launches should be competed,” Musk said.
“If we compete and lose that’s fine. But why were they not even competed? That just doesn’t make sense.”
“So far we are most of the way through the certification process. And so far there have been zero changes to the rocket. Mostly it’s just been a paperwork exercise.”
“Since this is a large multiyear contract, why not wait a few months for the certification process to complete. And then do the competition. That seems very reasonable to me.”
Musk said it costs four times more to launch ULA’s Delta or Atlas rocket vs. a SpaceX Falcon rocket.
“The ULA rockets are basically four times more expensive than ours. So this contract is costing US taxpayers billions of dollars for no reason.”
“Each launch by ULA costs American taxpayers roughly $400 million per launch. They are insanely expensive. I don’t know why they are so expensive.”
The Falcon 9 lists for about $60 Million per launch, but rises to about $100 million after the certification costs are included, Musk explained.
“So yes the certification does make our Falcon 9 rocket more expensive. But not 400% more expensive.”
“Our rockets are 21st century design,” said Musk to obtain the most efficiency. He said ULA’s designs date back to the 90s and earlier with heritage hardware.
To date the Falcon 9 has already been used three times under a $1.6 Billion contract with NASA to launch the private SpaceX Dragon resupply vessel to the International Space Station (ISS) – most recently a week ago during the April 18 blastoff of the SpaceX CRS-3 mission from Cape Canaveral.
It is also being used to launch highly expensive communications satellites like SES-8 and Thaicom-6 for private companies to geostationary orbits.
“It just seems odd that if our vehicle is good enough for NASA and supporting a $100 billion space station, and it’s good enough for launching NASA science satellites, for launching complex commercial geostationary satellites, then there’s no reasonable basis for it not being capable of launching something quite simple like a GPS satellite,” said Musk.
“Our only option is to file a protest.”
Furthermore as I wrote here in a prior article, US National Security launches are now potentially at risk due to the ongoing crisis between Russian, Ukraine and Crimea because the RD-180 first stage engines powering the Atlas V are designed and manufactured in Russia by NPO Energomash, majority owned by the Russian Federation.
“The head of the Russian space sector, Dmitry Rogozin, was sanctioned by the White House in March 2014 in the wake of Russia’s aggression in Ukraine,” says SpaceX.
The RD-180 engine supply could be cut off in a worst case scenario if economic sanctions against Russia are increased by the Western allies.
ULA has a two year contingency supply of the RD-180’s and blueprints to begin production, if needed.
However in the event of a cutoff, it would take at least three to five years to start and certify RD-180 engine production somewhere in the US, a ULA spokesperson told me recently at Cape Canaveral.
This possibly leaves a 1 to 3 year gap with no Atlas V 1st stage engine supply.
The Delta IV rockets and engines by contrast are manufactured in the US.
“In light of international events, this seems like the wrong time to send hundreds of millions of dollars to the Kremlin,” said Musk.
“Yet, this is what the Air Force’s arrangement with ULA does, despite the fact that there are domestic alternatives available that do not rely on components from countries that pose a national security risk.”
Stay tuned here for Ken’s continuing SpaceX, Orbital Sciences, commercial space, Orion, Chang’e-3, LADEE, Mars rover, MAVEN, MOM and more planetary and human spaceflight news.
The keys to NASA’s historic launch Pad 39A that propelled humanity’s first man to walk on the Moon – Neil Armstrong – during the history making flight of Apollo 11, have been handed over to new owners, namely the private aerospace firm SpaceX for a new purpose – serving as a commercial launch facility.
NASA and Space Exploration Technologies Corporation (SpaceX) of Hawthorne, Calif., have just signed an agreement giving SpaceX rights to occupy and operate seaside Launch Complex 39A at the Kennedy Space Center (KSC) in Florida.
SpaceX was founded by billionaire, entrepreneur and space visionary Elon Musk.
SpaceX aims to give the now dormant pad a new lease on life in the emerging New Space era by revitalizing it as a commercial launch site for the company’s mammoth new Falcon Heavy rocket, currently under development, as well as for manned launches of the firm’s human rated Dragon spacecraft atop the Falcon 9 according to Gwynne Shotwell, president of SpaceX.
“We’ll make great use of this pad, I promise,” Shotwell told reporters at a briefing at the pad.
The liquid fueled Falcon Heavy will be the most powerful rocket in the world according to SpaceX, generating generating nearly four million pounds of liftoff thrust from 27 engines and thus significantly exceeding the power of the Delta IV Heavy manufactured by competitor United Launch Alliance.
Shotwell said renovations to pad 39A would start later this year. The maiden SpaceX launch from the complex is expected next year.
“We will launch the Falcon Heavy from here from this pad early next year,” Shotwell stated.
The SpaceX Dragon is one of three commercial crew vehicles being developed under a public-private partnership with NASA to ferry US astronauts to the International Space Station (ISS) and restore America’s human spaceflight capability lost since the shuttle’s retirement.
The Boeing CST-100 and Sierra Nevada Dream Chaser are also vying for the next round of private ‘space taxi’ funding from NASA.
Pad 39A has been inactive and mothballed since the last shuttle mission, STS-135, thundered to space in July 2011.
Not a single rocket has rolled up the ramp at KSC in nearly 3 years.
The new lease agreement was signed by NASA and SpaceX officials and announced onsite at Pad 39 at the briefing.
“Today this historic site from which numerous Apollo and space shuttle missions began and from which I first flew and left the planet on STS-61C on Columbia, is beginning a new mission as a commercial launch site,” said NASA Administrator Charles Bolden.
“While SpaceX will use pad 39A at Kennedy, about a mile away on pad 39B, we’re preparing for our deep space missions to an asteroid and eventually Mars. The parallel pads at Kennedy perfectly exemplify NASA’s parallel path for human spaceflight exploration — U.S. commercial companies providing access to low-Earth orbit and NASA deep space exploration missions at the same time.”
Under terms of the new agreement with NASA, the lease with SpaceX spans 20 years.
“It’s exciting that this storied NASA launch pad is opening a new chapter for space exploration and the commercial aerospace industry,” said Bolden.
SpaceX will also maintain and operate Pad 39A at its own expense, with no US federal funding from NASA.
Pad 39A will be SpaceX’s third launch site. The company also launches its Falcon 9 rockets from nearby Pad 40 on Cape Canaveral Air Force Station and a west coast pad on Vandenberg Air Force Base, Calif.
NASA determined that the agency no longer has a use for pad 39A since the end of the shuttle era and has been looking for a new tenant to take over responsibility and pay for maintenance of the launch complex. The agency awarded the lease to SpaceX in December 2013.
Instead, NASA decided to completely upgrade, renovate and modernize Pad 39As twin, namely Launch Pad 39B, and invested in converting it into a 21st Century launch complex.
NASA will use Pad 39B to launch the state of the art Orion crew vehicle atop the new Space Launch System (SLS) booster for voyages beyond Earth and taking humans back to the vicinity of the Moon and further out on deep space missions to Asteroids, Mars and beyond.
The first unmanned SLS test flight from Pad 39B is slated for late 2017.
Pad 39A was an active NASA launch pad for nearly 35 years starting back near the dawn of the Space Age in the 1960s.
Apollo 4 was the first NASA booster to blast off from Pad 39A on Nov. 9, 1967 during the historic inaugural test flight of the Saturn V moon rocket that eventually served to dispatch all six US manned lunar landing missions.
The closing NASA use of Pad 39A took place on July 8, 2011 with the launch of STS-135 and orbiter Atlantis on the final flight of the space shuttle era.
The four person STS-135 crew delivered the last US pressurized module to the massive low-Earth orbiting ISS.
No Americans have launched to space from American soil since STS-135.
Launch Complex 39 was originally constructed to launch the Apollo moon landing missions atop NASA’s Saturn V booster in the 1960s and 1970s. Both pads were later modified to support the Space Shuttle program whose first launch took place in 1981 from pad 39A.
“Kennedy Space Center is excited to welcome SpaceX to our growing list of partners,” Center Director Bob Cabana said. “As we continue to reconfigure and repurpose these tremendous facilities, it is gratifying to see our plan for a multi-user spaceport shared by government and commercial partners coming to fruition.”
Stay tuned here for Ken’s continuing SpaceX, Orbital Sciences, commercial space, Orion, Chang’e-3, LADEE, Mars rover, MAVEN, MOM and more planetary and human spaceflight news.
Some people like an adventure, but don’t want to leave their home behind — like old Carl in the movie “Up.” So, if you wanted to go to space and take your domicile with you, what would it take? Certainly more than thousands of balloons; it would likely take millions of dollars. The folks at the housing blog Movoto Real Estate wanted to know just how much, saying they were inspired by the upcoming commercial launch by SpaceX to the International Space Station. Using launch costs for the Falcon Heavy, they computed an approximate weight-to-square-foot ratio of 200 pounds per square foot for a single story house and put in other variables. They built a “Home Blastoff Calculator” — an interactive infographic that allows anyone to figure out how much it cost to launch their house into space — noting that they computed weight, not volume. While certainly not feasible, it’s an interesting and fun concept, and the infographic also provides comparisons of launching other things into space, like dogs or chimps, or what it takes to put people on the Moon.